[FLINK-9222][docs] add documentation for setting up Gradle projects

docs/_config.yml

@@ -34,6 +34,8 @@ version_title: "1.8-SNAPSHOT"
 # Branch on Github for this version
 github_branch: "master"
 
+# Plain Scala version is needed for e.g. the Gradle quickstart.
+scala_version: "2.11"
 # This suffix is appended to the Scala-dependent Maven artifact names
 scala_version_suffix: "_2.11"
 

docs/dev/projectsetup/java_api_quickstart.md

@@ -26,14 +26,24 @@ under the License.
 * This will be replaced by the TOC
 {:toc}
 
-Start working on your Flink Java program in a few simple steps.
 
+## Build Tools
 
-## Requirements
+Flink projects can be built with different build tools.
+In order to get started quickly, Flink provides project templates for the following build tools:
+
+- [Maven](#maven)
+- [Gradle](#gradle)
+
+These templates help you to set up the project structure and to create the initial build files.
+
+## Maven
+
+### Requirements
 
 The only requirements are working __Maven 3.0.4__ (or higher) and __Java 8.x__ installations.
 
-## Create Project
+### Create Project
 
 Use one of the following commands to __create a project__:
 
@@ -69,7 +79,7 @@ Use one of the following commands to __create a project__:
  {% endunless %}
 </div>
 
-## Inspect Project
+### Inspect Project
 
 There will be a new directory in your working directory. If you've used
 the _curl_ approach, the directory is called `quickstart`. Otherwise,
@@ -108,16 +118,220 @@ In Eclipse, choose
 box: `-Xmx800m`.
 In IntelliJ IDEA recommended way to change JVM options is from the `Help | Edit Custom VM Options` menu. See [this article](https://intellij-support.jetbrains.com/hc/en-us/articles/206544869-Configuring-JVM-options-and-platform-properties) for details. 
 
-## Build Project
+### Build Project
 
 If you want to __build/package your project__, go to your project directory and
 run the '`mvn clean package`' command.
 You will __find a JAR file__ that contains your application, plus connectors and libraries
 that you may have added as dependencies to the application: `target/<artifact-id>-<version>.jar`.
 
 __Note:__ If you use a different class than *StreamingJob* as the application's main class / entry point,
-we recommend you change the `mainClass` setting in the `pom.xml` file accordingly. That way, the Flink
-can run time application from the JAR file without additionally specifying the main class.
+we recommend you change the `mainClass` setting in the `pom.xml` file accordingly. That way, Flink
+can run the application from the JAR file without additionally specifying the main class.
+
+## Gradle
+
+### Requirements
+
+The only requirements are working __Gradle 3.x__ (or higher) and __Java 8.x__ installations.
+
+### Create Project
+
+Use one of the following commands to __create a project__:
+
+<ul class="nav nav-tabs" style="border-bottom: none;">
+  <li class="active"><a href="#gradle-example" data-toggle="tab"><strong>Gradle example</strong></a></li>
+ <li><a href="#gradle-script" data-toggle="tab">Run the <strong>quickstart script</strong></a></li>
+</ul>
+<div class="tab-content">
+ <div class="tab-pane active" id="gradle-example">
+
+  <ul class="nav nav-tabs" style="border-bottom: none;">
+  <li class="active"><a href="#gradle-build" data-toggle="tab"><tt>build.gradle</tt></a></li>
+  <li><a href="#gradle-settings" data-toggle="tab"><tt>settings.gradle</tt></a></li>
+  </ul>
+  <div class="tab-content">
+<!-- NOTE: Any change to the build scripts here should also be reflected in flink-web/q/gradle-quickstart.sh !! -->
+  <div class="tab-pane active" id="gradle-build">
+  {% highlight gradle %}
+buildscript {
+ repositories {
+ jcenter() // this applies only to the Gradle 'Shadow' plugin
+ }
+ dependencies {
+ classpath 'com.github.jengelman.gradle.plugins:shadow:2.0.4'
+ }
+}
+
+plugins {
+ id 'java'
+ id 'application'
+ // shadow plugin to produce fat JARs
+ id 'com.github.johnrengelman.shadow' version '2.0.4'
+}
+
+
+// artifact properties
+group = 'org.myorg.quickstart'
+version = '0.1-SNAPSHOT'
+mainClassName = 'org.myorg.quickstart.StreamingJob'
+description = """Flink Quickstart Job"""
+
+ext {
+ javaVersion = '1.8'
+ flinkVersion = '{{ site.version }}'
+ scalaBinaryVersion = '{{ site.scala_version }}'
+ slf4jVersion = '1.7.7'
+ log4jVersion = '1.2.17'
+}
+
+
+sourceCompatibility = javaVersion
+targetCompatibility = javaVersion
+tasks.withType(JavaCompile) {
+ options.encoding = 'UTF-8'
+}
+
+applicationDefaultJvmArgs = ["-Dlog4j.configuration=log4j.properties"]
+
+task wrapper(type: Wrapper) {
+ gradleVersion = '3.1'
+}
+
+// declare where to find the dependencies of your project
+repositories {
+ mavenCentral()
+ maven { url "https://repository.apache.org/content/repositories/snapshots/" }
+}
+
+// NOTE: We cannot use "compileOnly" or "shadow" configurations since then we could not run code
+// in the IDE or with "gradle run". We also cannot exclude transitive dependencies from the
+// shadowJar yet (see https://github.com/johnrengelman/shadow/issues/159).
+// -> Explicitly define the // libraries we want to be included in the "flinkShadowJar" configuration!
+configurations {
+ flinkShadowJar // dependencies which go into the shadowJar
+
+ // always exclude these (also from transitive dependencies) since they are provided by Flink
+ flinkShadowJar.exclude group: 'org.apache.flink', module: 'force-shading'
+ flinkShadowJar.exclude group: 'com.google.code.findbugs', module: 'jsr305'
+ flinkShadowJar.exclude group: 'org.slf4j'
+ flinkShadowJar.exclude group: 'log4j'
+}
+
+// declare the dependencies for your production and test code
+dependencies {
+ // --------------------------------------------------------------
+ // Compile-time dependencies that should NOT be part of the
+ // shadow jar and are provided in the lib folder of Flink
+ // --------------------------------------------------------------
+ compile "org.apache.flink:flink-java:${flinkVersion}"
+ compile "org.apache.flink:flink-streaming-java_${scalaBinaryVersion}:${flinkVersion}"
+
+ // --------------------------------------------------------------
+ // Dependencies that should be part of the shadow jar, e.g.
+ // connectors. These must be in the flinkShadowJar configuration!
+ // --------------------------------------------------------------
+ //flinkShadowJar "org.apache.flink:flink-connector-kafka-0.11_${scalaBinaryVersion}:${flinkVersion}"
+
+ compile "log4j:log4j:${log4jVersion}"
+ compile "org.slf4j:slf4j-log4j12:${slf4jVersion}"
+
+ // Add test dependencies here.
+ // testCompile "junit:junit:4.12"
+}
+
+// make compileOnly dependencies available for tests:
+sourceSets {
+ main.compileClasspath += configurations.flinkShadowJar
+ main.runtimeClasspath += configurations.flinkShadowJar
+
+ test.compileClasspath += configurations.flinkShadowJar
+ test.runtimeClasspath += configurations.flinkShadowJar
+
+ javadoc.classpath += configurations.flinkShadowJar
+}
+
+run.classpath = sourceSets.main.runtimeClasspath
+
+jar {
+ manifest {
+ attributes 'Built-By': System.getProperty('user.name'),
+ 'Build-Jdk': System.getProperty('java.version')
+ }
+}
+
+shadowJar {
+ configurations = [project.configurations.flinkShadowJar]
+}
+ {% endhighlight %}
+ </div>
+ <div class="tab-pane" id="gradle-settings">
+ {% highlight gradle %}
+rootProject.name = 'quickstart'
+ {% endhighlight %}
+ </div>
+ </div>
+ </div>
+
+ <div class="tab-pane" id="gradle-script">
+ {% highlight bash %}
+ bash -c "$(curl https://flink.apache.org/q/gradle-quickstart.sh)" -- {{site.version}} {{site.scala_version}}
+ {% endhighlight %}
+ This allows you to <strong>name your newly created project</strong>. It will interactively ask
+ you for the project name, organization (also used for the package name), project version,
+ Scala and Flink version.
+ </div>
+</div>
+
+### Inspect Project
+
+There will be a new directory in your working directory based on the
+project name you provided, e.g. for `quickstart`:
+
+{% highlight bash %}
+$ tree quickstart/
+quickstart/
+├── README
+├── build.gradle
+├── settings.gradle
+└── src
+ └── main
+ ├── java
+ │   └── org
+ │   └── myorg
+ │   └── quickstart
+ │   ├── BatchJob.java
+ │   └── StreamingJob.java
+ └── resources
+ └── log4j.properties
+{% endhighlight %}
+
+The sample project is a __Gradle project__, which contains two classes: _StreamingJob_ and _BatchJob_ are the basic skeleton programs for a *DataStream* and *DataSet* program.
+The _main_ method is the entry point of the program, both for in-IDE testing/execution and for proper deployments.
+
+We recommend you __import this project into your IDE__ to develop and
+test it. IntelliJ IDEA supports Gradle projects after installing the `Gradle` plugin.
+Eclipse does so via the [Eclipse Buildship](https://projects.eclipse.org/projects/tools.buildship) plugin
+(make sure to specify a Gradle version >= 3.0 in the last step of the import wizard; the `shadow` plugin requires it).
+You may also use [Gradle's IDE integration](https://docs.gradle.org/current/userguide/userguide.html#ide-integration)
+to create project files from Gradle.
+
+
+*A note to Mac OS X users*: The default JVM heapsize for Java may be too
+small for Flink. You have to manually increase it. In Eclipse, choose
+`Run Configurations -> Arguments` and write into the `VM Arguments`
+box: `-Xmx800m`.
+
+### Build Project
+
+If you want to __build/package your project__, go to your project directory and
+run the '`gradle clean shadowJar`' command.
+You will __find a JAR file__ that contains your application, plus connectors and libraries
+that you may have added as dependencies to the application: `build/libs/<project-name>-<version>-all.jar`.
+
+__Note:__ If you use a different class than *StreamingJob* as the application's main class / entry point,
+we recommend you change the `mainClassName` setting in the `build.gradle` file accordingly. That way, Flink
+can run the application from the JAR file without additionally specifying the main class.
 
 ## Next Steps